In my U.S. Pat. Nos. 4,134,905; 4,163,744; 4,174,345; 4,183,852 and 4,217,279, I describe syntheses for the preparation of 25-hydroxycholesterol and its derivatives from 24-carbon-24-alcohol steroids with protected 3- and 6-hydroxyl or ketone groups. Included in these syntheses is the extension of the side chain of the 24-carbon-24-alcohol steroid with a cyano group to a 25-carbon steroid.
Steroid aldehydes have been prepared by ozonization of dibromostigmasterol acetate to yield 3-acetoxy-bis 5-cholenaldehyde and from thiol esters of deoxycholic acid, 3.beta.-hydroxy-5-cholenic and -bisnor-5-cholenic acid to yield the corresponding steroid aldehydes, by desulfurizing said thiol esters with Raney nickel. These procedures were described in the following publications: A. P. Certolella et al, JACS, 70, 2953 (1948); R. H. Levine et al, ibid, 70, 511 (1948); G. B. Spero et al, ibid, 70, 1907 (1948); and A. V. McIntosh et al, ibid, 70, 2955 (1948).